Methods of attitude and misalignment estimation for constraint free portable navigation

Abstract

The present disclosure relates to methods of enhancing a navigation solution about a device and a platform, wherein the mobility of the device may be constrained or unconstrained within the platform, and wherein the navigation solution is provided even in the absence of normal navigational information updates (such as, for example, GNSS). More specifically, the present method comprises utilizing measurements from sensors (e.g. accelerometers, gyroscopes, magnetometers etc.) within the device to calculate and resolve the attitude of the device and the platform, and the attitude misalignment between the device and the platform.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Patent Application No. 61 / 466,840 filed Mar. 23, 2011, the entire disclosure of which is considered to be part of the present disclosure and is hereby incorporated by reference.TECHNICAL FIELD[0002]The present invention relates to methods for detecting and estimating attitude of a device and a platform (such as for example person or vehicle) and the misalignment between them for enhancing a navigation solution, wherein mobility of the device may be constrained or unconstrained within the platform.BACKGROUND OF THE INVENTION[0003]Inertial navigation of a platform is based upon the integration of specific forces and angular rates measured by inertial sensors (e.g. accelerometer, gyroscopes) by a device containing the sensors. In general, the device is positioned within the platform and commonly tethered to the platform. Such measurements from the device may be used to determine the positi...

AI Technical Summary

Benefits of technology

The patent describes a method for accurately determining the position of a device within a platform, regardless of the device's orientation or the platform's mobility. This is achieved by detecting and estimating the absolute position of the platform and the device, and accounting for any misalignment between them. The method can improve the user experience by enhancing the navigation solution provided for devices with constrained or unconstrained mobility. Noise reduction techniques can be used to improve the accuracy of the received signal strength measurements. Overall, the technical effects of the patent include improved accuracy and reliability of navigation solutions for devices in various environments and scenarios.

Problems solved by technology

1) absolute attitude angles for the device and the platform;

2) absolute attitude angles for the device and the misalignment between the device and platform;

3) absolute attitude angles for the platform and the misalignment between the device and platform.

The above methods, however, are not applicable for circumstances where the movement of the platform may not satisfy the required criterion, for example, where the platform is a person walking.

Despite these two positioning methods that already come in many mobile devices, accurate indoor localization still presents a challenge and fails to satisfy the accuracy demands of today's location based services (LBS).

Additionally, these methods may only provide the absolute heading of the platform without any information on the device's heading.

Furthermore, the current available techniques need pre-knowledge about the environments and there are no known techniques for WiFi positioning in any new or user-unknown environment.

These sensors have been considered unusable to date for navigation purposes due to very high noise, large random drift rates, and frequently changing orientations with respect to the carrying platform or person.

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